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· Just another modeller
9,967 Posts
HI Matt, I enjoy your positive enthusiasm for the subject:

As one who is directly involved and who also worked damned hard sometimes quietly sometimes not to get Hornby off its high horse and onto the DCC bandwagon for several years I think that the horrible experience of Select and hornby decoder owners is proof positive that a global standard is very desirable.

quite sophisticated Analog multi-train control and more latterly DCC variants had several false starts over 30 years or so, and if a standards based approach had been followed in those early years, it'd be in a very advanced state right now.

Doug, I really do think that the answer to your question is moot: Digital control would be a fragmented and sad shadow of where it is today without it. Warrants by the way do not cover the firware, but are based on the nature of the physical outputs + the consistencey of a very small part of the the command and communication structure. every firmware change or revision does not invalidate a conformance warrant unless it changes these factors negatively.

To clarify:
Conformant: has been submitted for NMRA testing and passed the tests. a system cannot be called conformant unless its been tested by thenmra themselves.

Compliant: has been self tested and is warranted to comply. a product cannot use the term compliant and the dcc logo unless it meets the standards. if a Mfr does this then the NMRA will get on their case.

The CE and FCC issue.

The standards actually already allow for this and it has been acknowledged for quite some time that the system needs to comply with the local market regulation in which it is sold in order to be compliant or conformant. Removal of the term FCC is a good idea, but its presence has not stopepd any product being certified if it was not to be sold in USA.

FCC cerification is actually less rigid and draconian than CE testing by a country mile.

Why don't many companies go the whole way and do the conformance: basically NMRA is a volunteer organisation and NOT a regulatory body.

Its a volunteer manned organisation so its very structure makes it very difficult.

Timing has been slow and manufacturers who fully understand the specification have peferred to make damned sure it is compliant before release rather than accept an added significant delay due to conformance testing.

Basically the move to create a self test platform by the NMRA was an acknowedgement of this, and when completed will be a pragmatic and practical answer to much of the problem.

Its still under very delayed development but when finalised it will provide a complete test and analysis platform nad the process will require a set of data to be created utilising the self test equipment which would then be duly notarised and registered.

Manufacturers are keen for this to happen and are supporting the move BUT the contractor engaged by the NMRA is a light year behind on delivery. I should add its not going to be a cheap bit of kit either, and will be a stretch for the smaller businesses responsible for much of the positive evolution of DCC accessories!

You should not underestimate the ability of the market and the NMRA, volunteers or not, to act if a Mfr misuses the conformance claim ability - NMRA does not want to be and cannot be a "DCC police" but there are caring and responsible people in every part of the world that can and do act with good success where problems arise.

The problem is only where the arrogance of the manufacturer tries to take advantage of the term DCC and then openly flaunts its specification. This is what Hornby did with its initial releases until eventually, publicity and market forces - largely YOU as users, let it be known that it wasn't going to be accepted.

Yes... there are many who either use both or just prefer compliance only because it doesn't delay them but have you noticed it is also they who often lead the pack in design and feature innovation. NCE, Digitrax, ESU(ecos), almost all EU suppliers except lenz (who is currently at the back of the pack software-wise anyway).

They do it not because they couldn't be conformant (because universally they can...) but because they cannot afford to wait to bring a product to market and lose the timing edge that is critical to all marketing.

Be aware too that you need to be careful what you wish for :).

Standards are actually evolving and WILL change constantly. - what complied yesterday may not tomorrow. good example - the beloved 8 pin plug will be phased out and no longer be a standard.... in favour of a whole suite of new ones - good for the Mfrs, a bitch for DCC modellers for a decade to come I predict!

NMRA is currently working to try to bring the reluctant ones to heel and would love a more complete set of brands who are conformant but is actually comfortable with compliance as long as its properly done

final comments: Compliance and conformance are actually dead easy to achieve.

For decoders there is only the very basic things such as CV29 and a couple of others such as DC/DCCcompatiblity and minor compulsory CV use... interestingly guess which decoder brand fails even this?

Standards are also very narrow and minor in command station terms in that they really only cover the quailty of the waveform and primary issues like voltages at track etc.

The amazing thing is that product so far off spec when released they are not even entitled to be called DCC can EVER be created- and without naming names, both still are techincally well off being "fit for market".

Standards should be throughout: What is truly needed is:

(1) that we vote with our feet and do NOT accept partial solutions such as H's or attitudes such as SK's. - where one product is now conformant because it was in real terms forced to be by market attitude but others are still unfit for sale.

(2) that the standards continue to evolve - Current DCC still revolves around & uses 1980's technology at its core and its way past time for the whole of the standards to be revisited and adopt initiatives that have already been possible for a long time. As a comaprison take a look at the bus specification for ESU's MFX (developed for marklin) and traditional DCC.

(3) Things like long address and aliasing must become part of the standards, as should things like both regulated methods for programming on the main and programming track, unrush currents for sound decoders, absolutely rigid use of higher functions (MRC gaugemaster for example fail to follow standards there) and most of the current "core RPs" (recommended practices) should now become standards, not recommendations.

many of these things are under active consideration, as is the very nature of the DCC bus.

Matthew: You should apply to join the NMRA working Group if you have not already done so. Standards can only work if the energy is applied properly at the roots. It may be frustrating making progress but it can only come from energy applied within. Such things are better done from within than from a soapbox.


PS: I've said my piece on this and similar subjects many times, and the above sums up my feelings. I'm happy to respond to issues where there is value in it, but l don't want to play tennis with the subject for the sake of it.

· Just another modeller
9,967 Posts
QUOTE (Matthew Peddlesden @ 10 Apr 2008, 19:59) <{POST_SNAPBACK}>- and our advice is ALWAYS to check the Warrant list and ONLY to buy kit with the conformance warrant because it provides that level of confidence about the compatibility of the kit. The problem is, there's next to nothing on the list at the moment! We do talk about non-warranted kit but only really in terms of encouraging them to try it out and then talk to the manufacturer about getting it certified if they like it.

I hope the discussion will proceed positively and constructively with a view to improving the standardisation situation for DCC, thanks for your time reading and contributing.


***One small point there Matt:

I totally agree with the posititive intent of the concept but beware - some conformant product is markedly inferior to compliant product of other brands, so using the existence of the warrant as the sole arbiter of choice at this point in time is not necessarily doing the punters a positive service.

I DO most sincerely look forward to a time when that will not be the case, however I think some things have to change before it becomes correct - the warrants need a use by date added, they need to be far more universally applied for and the standards themselves need to be updated to adopt todays DCC possibilities as compulsory rather than optional features or abilities.

I strongly agree with lobbying at every opportunity to encourage Mfrs to apply for conformance though - that goes without saying.


· Just another modeller
9,967 Posts
Matt - I am an NMRA member, a registered DCC Mfr and part of two of the DCC working groups - so I have no confusion or grayness about this issue at all.... I agree its a bit "jelly like" in interpretation (as are some of the RP's in fact) but the intention is to certify wihout creating an unusual burden on the Mfr - so there IS and there MUST be a degree of acceptance of integrity on behalf of the Mfrs.

If it was perfect, the terms wouldn't actually matter as we'd not even need to discuss it!

I had almost the same conversation as you with senior members of the NMRA quite some time ago, and again with the NMRA president (touching largely about the difficulties of a volunteer organisation creating mandates for Mfrs) by email 12 months ago.

Software versions change in decoders sometimes ten times a year and in "online updateable" DCC systems aspects of the code will change and be refined many many times per year... Not in substance, but in detail. In the PROM based systems some code will almost certainly change in detail change batch by batch. each will end up with a slight version number change...and this has never been considered to require a re-test. Bear in mind we aren't talking wholesale differences or anything that affects the primary DCC signal at all in 99.9% of cases.

Therefore there will always be changes from the precise unit submitted to the NMRA, however these changes will usually be to enhance and improve, not to take the unit away from the standard... All are positives and no sane Mfr who really wants to do well will play games with the standards, and those products which prove less than compatible in the real world are very soon reamed well and truly by the consumers as they should be.

There DOES need to be a mechanism to cope with it comfortably now more are moving from PROM to purely software based or flash upgradeable devices. THAT is why I said that I think that certification should have a date base or "use by date"

- so re-testing could be done routinely and to a schedule that both sides could cope with without adding too much of a burden anywhere.

Incidentally, the "family product" concept also exists in the quite draconian CE regulations - for example an audio amplifier range or CD player range only requires ONE product to be fully tested and the others can be covered by self declaration up to a point. This was added as a pragmatic way to prevent cost blowout for compliance and encourage Mfrs. A good idea!

The BIG advantage that CE has is that in case of naughtyness, the fines are huge - I wish the NMRA had such power (cause then they'd also have the same budgets and be able to test quicker)

In the end I wonder how it will pan out.

Ideally the self test which is done by the "in process of being created" NMRA created test gear with dedicated software embedded is a great answer, because results can then only be acurate so self testing would have a built-in "judgement" and Mfrs could use it for pre-evaluation too, which would make the Mfrs job so much easier, increase participation in the programme and leep time to market much quicker!

Re the conformance and compliant thing. I actually agree with you but the NMRA created the two terms in the first place, during a period where they were looking for cooperation but feeling toothless..

NMRA permit and in some ways have in the past encouraged the use of the term DCC compatible but the NMRA DCC football has only ever been permitted to adorn packaging if the product has passed NMRA testing.

THIS issue is also being (or is supposed to be being) revisited in an attempt to take firmer hold of the situation right now, but will still take a while to come into effect. Very few Mfrs ever abused this issue.

Hopefully, a fresh global DCC logo with a much more significant meaning will evolve!

Interestingly Hornby was the ONLY major brand in memory apart from MRC to misuse the DCC concept and branding so badly and miss the mark by so far - so getting them back in line was important... So while I am still of the opinion they have to fix the other products properly, I'm very very positive about their new found approach to elite.

I smile at their option of "classic and Standard DCC operation" though... cheeky buggers, how can a cockup be "classic" :) :)

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